From: Jens Axboe <axboe@kernel.dk>
To: Vladimir Davydov <vdavydov@parallels.com>
Cc: Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
devel@openvz.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] block: account iowait time when waiting for completion of IO request
Date: Fri, 15 Feb 2013 16:44:21 +0100 [thread overview]
Message-ID: <20130215154421.GA6131@kernel.dk> (raw)
In-Reply-To: <d1fdb105fe23f979871b92c4b4d3dd374146e337.1360851174.git.vdavydov@parallels.com>
On Thu, Feb 14 2013, Vladimir Davydov wrote:
> Using wait_for_completion() for waiting for a IO request to be executed
> results in wrong iowait time accounting. For example, a system having
> the only task doing write() and fdatasync() on a block device can be
> reported being idle instead of iowaiting as it should because
> blkdev_issue_flush() calls wait_for_completion() which in turn calls
> schedule() that does not increment the iowait proc counter and thus does
> not turn on iowait time accounting.
>
> The patch makes block layer use wait_for_completion_io() instead of
> wait_for_completion() where appropriate to account iowait time
> correctly.
Thanks, applied both for 3.9 (with Ingos ack).
--
Jens Axboe
next prev parent reply other threads:[~2013-02-15 15:45 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-14 14:19 [PATCH 1/2] sched: add wait_for_completion_io[_timeout] Vladimir Davydov
2013-02-14 14:19 ` [PATCH 2/2] block: account iowait time when waiting for completion of IO request Vladimir Davydov
2013-02-15 15:44 ` Jens Axboe [this message]
2013-02-15 15:41 ` [PATCH 1/2] sched: add wait_for_completion_io[_timeout] Ingo Molnar
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20130215154421.GA6131@kernel.dk \
--to=axboe@kernel.dk \
--cc=devel@openvz.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=vdavydov@parallels.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.